Floor panel for an elevated floor assembly

ABSTRACT

A floor panel to be used in an elevated floor assembly, includes a flat top sheet receptive to a tread surface and a drawn bottom plate secured to the top sheet. The bottom plate is formed to present a plurality of radial ribs that intersect one another centrally of the panel and extend to merge with peripheral ribs that edge the four sides of the panel. The sides of the ribs web the sheet and plate together to form hollow box sectioned beams as peripheral ribs and radial ribs of the panel. A cross-shaped stiffener with ridges is positioned between the sheet and the plate. The ridges are oriented to coextend with the radial ribs and the side edges of the stiffener are secured to the underside of the top sheet. A trim member is wedged between the edge of the sheet and the rim of the plate to abut the tread surface. The panel can be perforated to permit air circulation and the perforations do not cause any significant loss of structural strength.

United States Patent Swensen et al.

[451 Oct. 10,1972

[54] FLOOR PANEL FOR AN ELEVATED FLOOR ASSEMBLY [72] Inventors: Eugene L. Swensen, Rockville; Franklin E. Gibson, Baltimore, both of Md.

[73] Assignee: Liskey Aluminum, Inc., Elkridge Landing Road, near Baltimore Friendship Airport, Md.

[22] Filed: March 6, 1970 [21] Appl. No.: 17,225

[52] US. Cl. ..52/618, 52/126, 52/619, 52/630 [51] Int. Cl ..E04c 2/32 [58] Field of Search ..52/126, 263, 614, 618, 615, 52/619, 620, 630

[56] References Cited UNITED STATES PATENTS 3,236,018 2/1966 Graham et al. ..52/619 3,388,516 6/1968 Thielen ..52/618 3,548,559 12/1970 Levine ..52/620 3,568,390 3/1971 Swensen et al. ..52/619 3,420,012 1/1969 Liskey, Jr. et a1. ..52/126 3,396,501 8/1968 Tate ..52/619 2,616,529 11/1952 MacDonald ..52/303 3,540,116 11/1970 Drahos et a1. ..52/619 FOREIGN PATENTS OR APPLICATIONS 832,231 9/1938 France ..52/618 232,845 4/1969 U.S.S.R. ..52/615 548,041 8/1958 Italy ..52/615 561,214 5/1944 Great Britain ..52/615 Primary ExaminerFrank L. Abbott Assistant Examiner-Leslie A. Braun Attorney-Mason, Mason & Albright [57] ABSTRACT A floor panel to be used in an elevated floor assembly,

includes a flat top sheet receptive to a tread surface and a drawn bottom plate secured to the top sheet. The bottom plate is formed to present a plurality of radial ribs that intersect one another centrally of the panel and extend to merge with peripheral ribs that edge the four sides of the panel. The sides of the ribs web the sheet and plate together to form hollow box sectioned beams as peripheral ribs and radial ribs of the panel. A cross-shaped stiffener with ridges is positioned between the sheet and the plate. The ridges are oriented to coextend with the radial ribs and the side edges of the stiffener are secured to the underside of the top sheet. A trim member is wedged between the edge of the sheet and the rim of the plate to abut the tread surface. The panel can be perforated to permit air circulation and the perforations do not cause any significant loss of structural strength.

8 Claims, 10 Drawing Figures PATENTEDncI 10 1912 SHEET 1 BF 4 FIG. 1

2 INVENTORS EUGENE L. SWENSEN FRANKLIN E. GIBSON W 44% TORNEYS PATENTEDHN 10 I912 3 696; 57s

SHEET 2 OF 4 INVEN'IOBS EUGENE L. SWENSEN FRANKLIN E. GIBSON PATENTEDnm 10 m .sum 3 OF 4 FIG. 5 I

INVENTORS EUGENE L. SWENSEN FRANKLIN E. GIBSON ATTORNEYS PATENTEMBT 10 m2 3-. 696. 578 sum u OF 4 IINVENTORS EUGENE L. SWENSEN FRANKLIN E. GIBSON TORNEYS FLOOR PANEL FOR AN ELEVATED FLOOR ASSEMBLY BACKGROUND OF THE INVENTION This invention relates to a floor panel of the type used in elevated floor assemblies with understructu're supports. Such floor panels are preferably modular, square and supported at their comers by pedestals as disclosed in US. Pat. 3,420,012 and US. copending applications Ser. No. 801,442 now US. Pat. No.

3,568,390 filed Feb. 24, I969, and Elevated Floor As sembly, filed Jan. 6, 1970, now US. Pat. No. 3,616,584 naming Eugene L. Swensen as coinventor. The panels can be assembled with or without stringers bridging the pedestals.

SUMMARY OF THE INVENTION Elevated access floors are widely used in computer rooms to provide sub fioor space for the multitude of wires, cables and accessory equipment associated with the machinery that rests on the access floors. The panels which make up such floors must be strong enough to support heavy machinery, yet readily removable so that access can be had to all parts of the electrical equipment. At the same time, the access floor panels define an air plenum with the original floor so that air at controlled temperature and humidity can be circulated to all parts of the computer equipment.

The panel of the instant invention, in either its perforated or non-perforated form, is designed to be particularly resistant to deformation and deflection under heavy load so that the integrity of the entire floor is preserved even after heavy machinery is installed. Further, the panel disclosed herein can be used with or without stringers bridging the pedestals depending on the intended use of the access floor.

It is an object of this invention to provide a panel of improved performance while at the same time reducing the number of elements and inherent manufacturing costs.

It is another object of this invention to provide a floor panel that has a high strength to weight ratio, even where different materials such as plastic, aluminum or steel are used to form the panel.

It is still another object to provide a panel in which local deflections under load are minimized even in relatively unsupported areas.

It is still a further object to provide a panel in which a resilient edge trim is securely held by built-in features of the panel thereby permitting the panel to be fitted in place and roughly handled without trim dislodgement.

It is a further object of this invention to provide a floor panel in which perforations for air passage can be made without compromising the structural continuity of the panel so that it can be used in heavy equipment areas such as computer rooms.

It is still another object to provide a panel in which a number of perforations can be made in the recessed areas adjoining the peripheral and radial ribs of the panel to provide a floor panel that has a particular resistance to deformation and deflection under heavy load and still allows the passage of air for cooling heavy machinery from the underfloor plenum formed by an assembly of floor panels.

It is a further object to provide a panel which allows the passage of air in controlled amounts by dampering the perforated areas of the floor panel.

It is still a further object to provide a panel which allows the passage of air and es'thetically blends wit with other floor panels by perforating the completed panel so that resilient floor coverings as well as the laminated plastic floor coverings can be used.

It is also a object to provide a panel which allows the passage of air and which can be removed from an assembly of floor panels using a standard suction lifting device without removing or disturbing adjacent floor panels.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a bottom plan view of the panel showing the radial and peripheral ribs formed in the lower plate;

FIG. 2 is a section view taken along lines 2--2 of FIG. 1 showing the edge configuration of a finished panel;

FIG. 3 is a section view taken along lines 3--3 of FIG. 1 showing the radial rib configuration of the lower plate as attached to a finished panel; FIG. 4 is a section view taken along lines 4-4 of FIG. 1 showing the relative position of the internal stiffener inside a radial rib of the lower plate and as attached to the upper sheet;

FIG. 5 is a top plan view of the panel with the top sheet removed to show the cruciform shape and position of the intermediate stiffener.

FIG. 6 is a section view showing the interfitting edges of abutting panels on a stringer;

FIG. 7 is a section view showing the interfitting edges of abutting panels on a pedestal cap;

FIG. 8 is a schematic drawing of the strengthened panel with beam construction;

FIG. 9 is a bottom pan view of the FIG. I panel which has been perforated; and

FIG. 10 is a section view taken along the lines IO 10 of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, the floor panel 1 is shown in plan view with a drawn bottom plate 10 in which eight radial raised ribs 3 intersect in the approximate center 5 of the panel. The ribs 3 extend outwardly from center 5 to merge with peripheral raised ribs 7 which border the peripheries of the panel. The ribs 3 and 7 form undulations in which a plurality (preferably eight) of right triangles are formed. The interior spaces 20 of the triangles overlie, and are attached to top sheet 11, preferably by spot welding in the instance of steel. Sloped webs 30 of the ribs interconnect the apices 31 of ribs 3 with the spaces 20 and sheet 1 1.

As seen in FIG. 2, peripheral ribs 7 are formed along the edges of the panel and top sheet l 1 bridges the ribs, being welded or otherwise attached to plate 10 on both sides of ribs 7 to form box beams. Each side of plate 10 has an outer rim 34 that is bent in a hook shape to terminate adjacent the outer edge of sheet 11. A snapon trim member 13 is wedged between the rim 34 and the edge of sheet 11 to abut tread surface 12 adhered to sheet 11 and present a continuous, smooth upper surface. At the comers 36, the hook-shaped rims are split to simplify production.

In FIG. 3, radial rib 3 is shown in the form of a U- shape with spot welds x on either side of the rib 3 where sheet 11 and plate 10 meet adjacent the ribs. With this structure, boxed beams are inherently formed and reduce load deflection.

In FIG. 5, a stiffener 14 is shown with four equally spaced apart arms 40 with ridges 15 in cruciform shape. The arms 40 coextend within corresponding ribs 3 for about one third or one half the lengths of the ribs 3. The stiffener 14 is preferably welded to the top sheet 11 as seen in FIG. 4. The spot welds x seen in FIG. 5 generally show suitable locations of same, the top sheet 11 being removed to show stiffener 14 which is sandwiched between sheet 11 and plate within the hollow, central panel section.

The primary purpose of the internal stiffener 14 is to provide local support or added stiffness to that central triangular indentations of the lower plate 10.

It can be shown that the internal stiffener 14, when attached to the top sheet 1 1 provides another box beam for approximately one third or more of the overall panel span, which is normally 24 inches. The combination of sheets 11 and 14 then, form individual beams in the central section of the panel where the sloping webs of the radial ribs 3 transition and disappear. The unique combinations of members 10, l1 and 14 represent, in total, a hybrid beam construction shown schematically in FIG. 8 where the central section is a beam formed of the top sheet 11 and the stiffener 14; the outer sections are beams formed by the lower sheet 10 and the top sheet 1 1, and the flat central section 10a of the formed bottom plate 10 becomes a true tension member.

In FIG. 6, two abutting panels 1 are shown in section similar to FIG. 2, with their hook-shaped rims 34 interfitting over the indented top 350 of stringer 31a.- The stringer 31a can be the same as that disclosed in the aforementioned copending application filed Jan. 6, 1970.

In FIG. 7, the same two panels 1 are shown closely abutting one another on the pedestal cap 110 of pedestal 21 when no stringers are used. In each instance of the FIG. 6 and FIG. 7 structures, hook-shaped rims 34 interfit with matching faces on the understructure supports to insure the proper spacing of panels and pedestals. The pedestals can be the same as disclosed in the above-listed copending application. It will be noted that the rims 34 are extended from ribs 7 to leave a margin 19 around the perimeter of the panel which forms a lip that is rested on the supporting understructure.

In the panel shown, the sheet and plate are each made of steel in the interests of strength, the former being about 0.07 inches and the latter about 0.06 inches. Obviously the thicknesses of the structural members can be varied depending on the intended use of the panels. The depth of the ribs 3 and 7 can be about I inch or more, preferably 1.25 or more. The trim member 13 as well as tread surface be of the vinyl material widely used in the floor til'et'rade.

A major design .criteria of the finished panelfis to limit, and reduce to the minimum, the deflections resulting from a vertical load imposed upon the panels upper surface and as such, it can be shown that the ribs 3 and 7 as well as ridges 15, when attached to sheet 11, form box section beams that are highly efficient for sustaining the resultant flexural stresses and thereby reducing deflections. The primary purpose of the combinations of sheet 10 and 11 when so attached is the formation of individual structural members. A secondary but extremely important feature of the top sheet 1 l is to provide a flat and smooth surface to which a tile or tread surface 12 can be adhered. It is considered important that this sheet 11 remain completely flat, that is, with no turned down flanges or other protuberances, in order that it may provide support to the full extremity of the tile surface.

In addition to the primary structural function of the plate 10, a secondary but vital added function is the unique manner in which the edge of the plate is utilized to retain the edge trim plastic 13 as shown in FIG. 2. It can be seen that'the short upturned flange at the extreme edge of the panel is produced flush with the edge trim 13 thereby protecting it from damage when a panel is placed in position within a floor system, even when roughly handled.

It can also be seen in FIG. 2 that the unique formation and attachment or positioning of sheet 11 and plate 10 provides an effective mechanical entrapment of the edge trim 13 in all directions thereby preventing trim breakage or dislodgement as happens with present known designs which employ a simple press on and glue concept. Specifically, the edge trim 13 is of resilient material so that the bottom ends can be pinched together and sandwiched between plate 10 and sheet 11. The vertical sides of trim l3 abut the panel to resist horizontal motion and opposite horizontal surfaces of the trim abut sheet 11 to prevent vertical motion. Thus trim 13 is restrained from dislodgement upward by the configuration of trim 13 which locks under the lower surface of the top sheet 11.

In FIGS. 9 and 10, the panel of FIG. 1 has been perforated so that when similar panels are assembled to form an elevated floor, air of controlled temperature and humidity can be circulated between the base floor and the elevated floor to pass through the perforations. Only one triangular space 20 is shown perforated but as many of the spaces 20 as desired can have perforations 40 formed therein. Further, only some of the panels may need to be formed with perforations depending on the effect desired in the assembled floor.

The perforations 40 are preferably formed by punching holes through the finished or completedv panel so that the tile 12 or other tread surface, including carpeting, is also perforated and the panel is ready for use. The holes are best made in the spaces 20 of the triangles so that none of the ribs 3 or 7, which are load bearing beams, are weakened structurally. Also, by punching the panels at those locations where the tread surface, the plate 10 and top sheet 11 meet, neither the stiffener nor the center are perforated and most, if not all, of the spot welds remain intact.

The perforations 40 can be formed in attractive patterns, and the individual perforations can-be about A inch in diameter with centers of adjacent perforations being about one-half inch apart. Obviously, however, other dimensions are suitable and the standard suction cup lifting handle known in the trade can be used to lift the panels at their centers. The perforations 40 can be dampered by triangular-shaped pieces of plastic that are placed to overlie the spaces 20.

What is claimed is:

1. A modular floor panel comprising a substantially flat top sheet and a bottom plate being formed with a plurality of raised rib means with side webs that space and connect apices of said rib means relative to said sheet, said rib means including radial ribs that intersect at the approximate center of said panel and extend towards the edges thereof, the intersection of said ribs being spaced apart from said sheet to define a hollow central, panel section, an internal stifiener secured to said panel within said hollow section and between said sheet and said plate, said stiffener being cruciform in configuration and having radial arms with raised ridges that form box beams to underlie and coextend with said radial ribs and said stiffener being fixed to the undersurface of said top sheet to terminate short of the outer periphery of said panel, said bottom plate having rims which define the outer perimeter of said panel and said top sheet having outer edges located within said outer perimeter.

2. The panel of claim 1 wherein said rib means includes rib elements that border the peripheries of said panel, said radial ribs intersecting at the approximate center of said panel and extending to merge with said rib elements whereby a plurality of right angles are formed, the internal areas of which meet and are secured to the undersurface of said top sheet.

3. The panel of claim 2 wherein a plurality of perforations are formed in said panel between said ribs and said rib elements to provide a floor panel that allows the passage of air.

4. The panel of claim 3 wherein a plurality of triangular-shaped spaces are formed between said ribs and said rib elements and said perforations being formed in said spaces.

5. The panel of claim 1 wherein said stiffener has four raised ridges each of which extends approximately one half the length of the radial rib under which the respective ridge is located.

6. The panel of claim 1 wherein said side rims are bent in a general hook shape adjacent the outer edges of said top sheet leaving a space between said rims and said outer edges, a resilient trim member being locked in position between said rims and edges, a tread surface overlying said sheet to abut said trim member.

7. The panel of claim 6 wherein said side rims extend beyond said rib means to form a supporting lip that rests on an understructure.

8. A modular floor panel comprising a substantially flat top sheet with outer edges and an underlying bottom plate with reinforcing rib means and integral lip means with side rims, said rib means being bent upwardly forming said lip means and side rims in a general hook shape, said side rims extending below said top sheet to leave a space, said side rims terminating adjacent the outer edges of said top sheet leaving a horizontal space between said rims and said outer edges, the hook-shaped portion of said lip means being load bearing, a resilient trim member being locked in the space between said rims and edges, a tread surface overlying said sheet to abut and be bordered by said trim member to form a smooth and level tread surface. 

1. A modular floor panel comprising a substantially flat top sheet and a bottom plate being formed with a plurality of raised rib means with side webs that space and connect apices of said rib means relative to said sheet, said rib means including radial ribs that intersect at the approximate center of said panel and extend towards the edges thereof, the intersection of said ribs being spaced apart from said sheet to define a hollow central, panel section, an internal stiffener secured to said panel within said hollow section and between said sheet and said plate, said stiffener being cruciform in configuration and having radial arms with raised ridges that form box beams to underlie and coextend with said radial ribs and said stiffener being fixed to the undersurface of said top sheet to terminate short of the outer periphery of said panel, said bottom plate having rims which define the outer perimeter of said panel and said toP sheet having outer edges located within said outer perimeter.
 2. The panel of claim 1 wherein said rib means includes rib elements that border the peripheries of said panel, said radial ribs intersecting at the approximate center of said panel and extending to merge with said rib elements whereby a plurality of right angles are formed, the internal areas of which meet and are secured to the undersurface of said top sheet.
 3. The panel of claim 2 wherein a plurality of perforations are formed in said panel between said ribs and said rib elements to provide a floor panel that allows the passage of air.
 4. The panel of claim 3 wherein a plurality of triangular-shaped spaces are formed between said ribs and said rib elements and said perforations being formed in said spaces.
 5. The panel of claim 1 wherein said stiffener has four raised ridges each of which extends approximately one half the length of the radial rib under which the respective ridge is located.
 6. The panel of claim 1 wherein said side rims are bent in a general hook shape adjacent the outer edges of said top sheet leaving a space between said rims and said outer edges, a resilient trim member being locked in position between said rims and edges, a tread surface overlying said sheet to abut said trim member.
 7. The panel of claim 6 wherein said side rims extend beyond said rib means to form a supporting lip that rests on an understructure.
 8. A modular floor panel comprising a substantially flat top sheet with outer edges and an underlying bottom plate with reinforcing rib means and integral lip means with side rims, said rib means being bent upwardly forming said lip means and side rims in a general hook shape, said side rims extending below said top sheet to leave a space, said side rims terminating adjacent the outer edges of said top sheet leaving a horizontal space between said rims and said outer edges, the hook-shaped portion of said lip means being load bearing, a resilient trim member being locked in the space between said rims and edges, a tread surface overlying said sheet to abut and be bordered by said trim member to form a smooth and level tread surface. 